1. Field of the Invention
The invention relates to an electrode for measuring a biomedical signal and an electrode support device for measuring a biomedical signal which are preferably used in a medical measuring apparatus for measuring vital information, such as an electroencephalograph or an electrocardiograph.
2. Related art
Conventionally, in MRI (Magnetic Resonance Instrument) diagnosis, an electroencephalogram or an electrocardiogram is measured. FIG. 10 is a view diagrammatically showing the configuration of MRI.
The case where an electroencephalogram or an electrocardiogram is to be obtained in MRI will be considered. In a strong magnetic field formed in MRI magnet of the MRI, a movement of the body of the subject causes a voltage in conformance to Faraday's law of electromagnetic induction to appear in lead wires of electrodes of an electroencephalograph or an electrocardiograph. Such a voltage functions as noises, and produces a problem in that the measurement cannot be correctly performed. This problem is produced also by a minute movement of the body of the subject caused by the heartbeat. Therefore, it is requested to develop a countermeasure to the problem as soon as possible. FIG. 11 shows an electrocardiogram and the waveform of noises. From the figure, it will be seen that noises appear in synchronization with the electrocardiogram. The noise level varies depending on the site to which an electrode is attached and the manner of drawing out a lead wire therefrom, and is in proportion to the number of crossing magnetic fluxes.